244 



THE MUSCLES OF THE LOWER LIMB. 



inserted into the small trochanter of the femur by means of a tendon, which is 

 placed at first within the substance of the muscle, and afterwards at its outer side, 

 receiving as it descends the fibres of the iliacus as well as those of the psoas. 



Relations. Both iliacus and psoas are covered in the abdomen by the iliac fascia, which 

 is also prolonged downwards over the conjoined muscle into the upper part of the thigh, where 

 it becomes continuous with the pubic portion of the fascia lata. Superficial to the fascia are 

 the subperitoneal fat and peritoneum, with the termination of the ileum, the caecum, and the 

 beginning of the ascending colon on the right side, and the lower part of the descending colon 

 on the left side. The psoas at its upper extremity is placed behind the diaphragm, being 



\ 



Fig. 248. DEEP MUSCLES OP THE ABDOMEN AND PELVIS. (Allen Thomson.) | 



a, twelfth dorsal vertebra ; &, fifth lumbar vertebra ; c, transverse process of the first lumbar ver- 

 tebra ; 1, quadratus lumborum muscle ; on the left side its fibres of origin from the transverse pro- 

 cesses of the lumbar vertebrae are shown by the removal of the psoas ; 2, placed upon one of the inter- 

 transvei-sales muscles of the left side ; 3, upper part of the psoas parvus, drawn somewhat to the outer 

 side ; 3', insertion of its tendon into the brim of the pelvis ; 4, psoas magnus ; 4", one of the origins of 

 the muscle ; 4', insertion of the muscle into the small trochanter of the femur ; 5, iliacus ; 5', insertion 

 of the outer fibres of the iliacus below the small trochanter ; 6, pyriformis muscle of the left side 

 arising within the pelvis from the sacrum ; 6', insertion of its tendon into the summit of the great 

 trochanter ; 7, obturator externus of the left side ; + +, crura of the diaphragm. 



crossed by the internal arched ligament ; and below this the kidney with the ureter and renal 

 vessels lie on the muscle, as well as the spermatic vessels and the genito-crural nerve. The 

 external iliac artery rests against its inner border along the brim of the pelvis, but lies over 

 the muscle as it enters the thigh. The lumbar plexus of nerves is imbedded deeply in the sub- 

 stance of the psoas, and its branches issue from the muscle at various points. The anterior 

 crural nerve passes into the thigh lying in the groove between the psoas and iliacus, and the 

 ilio-inguinal and external cutaneous nerves cross the surface of the iliacus. The iliacus lies 

 over the ilium, the anterior head of the rectus femoris, and the hip- joint, to the capsule of 

 which a few of its fibres are sometimes attached. The psoas rests against the vertebras, 



